Two small clips on the back secures the eyepiece onto your camera. - Replaces Nikon Eyecup DK-20. - Custom designed soft-touch eyecup to provide cushioning around the camera's eyepiece. - Block out unwanted light from your viewfinder. - Useful for eyeglass wearers and others to keep the tip of the nose from touching the camera body. DK-20 Eyepiece Eyecup Eye Cup Rubber For Nikon D5100 D3100 D3000 F65 F75 D40 D50 D70s D5100 D3200 D3100 D3000 Camera